There exists a general type of a high speed, continuous-motion automatic packaging machine known as the horizontal form-fill seal type of machine. Basically, this type of machine forms a horizontal tube of film from a roll of film and feeds product into the tube on a continuous basis in a properly spaced relationship. Each tube is sealed at its ends, and the tubes are cut apart between adjacent products on a continuous basis. To form completely wrapped packages, the transverse sealing and cutting mechanism of these machines generally includes either two mating jaws rotating about a central axis or two mating jaws always aligned vertically but driven in a circular orbit by variable speed crank mechanisms. Inherently in this type of mechanism, the actual type of contact of the seal bar with the film is extremely limited. However, as long as these machines were used with coated cellophane and other rapid-sealing film laminates, the seal dwell time limitation presented no problem. However, with the attempt to adapt this packaging principle and such known apparatus to certain classes of shrink film, specifically irradiated, medium-density polyethylene, it was found that the seal dwell limitation precluded the attainment of the desired range of transverse seal strength.
In addition, in machines of the prior art, the size of products to be packaged, in particular, the height of the package above the operating table was limited.